I think you kind of take it out on Batman more than he deserves. His position is that the oracle is essentially worthless and meaningless, and so the course of action she is on is unnecessary and hurtful, not to mention lessening the chances of success. He's not being a dick as much as he is not tolerating the idea that the future is preordained. And look at that, he's right. Is he being abrasive about it? well yeah, but we know that he looks up to Diana, and this sort of thing hurts coming from someone you expect the best of.